Chain ring with teeth oppositely laterally engaging a drive chain

ABSTRACT

A drive system for a vehicle includes a chain ring and a drive chain. The chain ring has a plurality of teeth serially arranged and joined to one another. A first subset of teeth has a first outer face that applies a lateral pressure to a link of a drive chain in a first direction. A second subset of teeth has a second outer face that applies a lateral pressure to another link of a drive chain in a second direction. The teeth all have substantially the same width. The top surfaces of the teeth are offset from the centerline of the drive chain. The centerlines of the top surfaces of the teeth are arranged asymmetrically on one side of the centerline of the drive chain.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application claims priority to U.S. Provisional PatentApplication Ser. No. 62/146,635, filed on Apr. 13, 2015, the disclosureof which is incorporated herein by reference.

STATEMENT REGARDING FEDERALLY-SPONSORED RESEARCH AND DEVELOPMENT

(Not Applicable)

REFERENCE TO AN APPENDIX

(Not Applicable)

BACKGROUND OF THE INVENTION

The present disclosure relates generally to a chain ring for a vehicle.More particularly, the present disclosure relates to a chain ring thathas alternating teeth that may form a wave pattern.

Drive chains used for vehicles like bicycles are formed of alternatinglinks. A first link has a narrow opening. The adjacent second links arewider. As may be seen best in FIG. 1, bicycle drive chains may be madefrom outer links 100 and inner links 102. In general, the length 104 ofeach link is about the same. However, the outer links 100 and the innerlinks 102 differ in width. The outer link 100 may have a width 106 widerthan the width 103 of the inner link 102. It will be understood by aperson having ordinary skill in the art that in a conventional bicycledrive chain, the series of alternating outer links 100 and inner links102 alternate for whatever length of drive chain is deemed desirable.The chain as a whole may be referred to as the chain 150.

A conventional chain ring is shown in FIG. 2. The chain ring 210includes a plurality of teeth 212 of substantially similar size andshape. The use of teeth of substantially similar size and shape mayallow for gaps between an outer surface 214 of a tooth 212 and a firstinner lateral surface 110 or a second inner lateral surface 112 of anouter link 100 of a drive chain (see FIG. 1). In many conventionalapplications, these gaps may not drastically hinder performance, but mayincrease the risk of chain disengagement.

In the past, some manufacturers have attempted to create chains thathave alternating teeth. These alternating teeth have been configured tocorrespond in size and shape more closely to the alternating width ofthe links in a chain. These teeth have typically been configured to havea set of narrow teeth alternating with a set of wider teeth. However,the use of teeth of larger size also may increase the weight of thechain ring and the vehicle, which may be deemed undesirable. Inaddition, the use of a tooth of larger size may, in some cases, increasethe risk of a tooth catching on a portion of the chain due to thatincreased size, thereby creating damage or risk of injury. Further, theuse of such a design may increase the likelihood of dirt, mud, or otherdebris becoming entangled in the ring and/or between the teeth of thering and impeding the meshing of the teeth and the chain.

BRIEF SUMMARY OF THE INVENTION

In one embodiment, a ring for driving a drive chain for a bicycleincludes a plurality of teeth that are connected to one another andserially arranged. Each of the plurality of teeth may have a thicknessand the thickness of each of the plurality of teeth at its respectivethickest point may be substantially identical. A first subset of theplurality of teeth may be configured to have a first cross-sectionalshape at a respective base and a second subset of the plurality of teethmay be configured to have a second cross-sectional shape at a respectivebase.

The first cross sectional shape may be rectangular. The secondcross-sectional shape may be non-rectangular. Each of the teeth in thefirst subset of teeth may be configured to fit within an inner link of abicycle drive chain. Each of the teeth in the second subset of teeth maybe configured to fit within an outer link of a bicycle drive chain. Eachof the teeth in the first subset of teeth may be configured to applylateral pressure in a first direction to a respective link of thebicycle drive chain; such a link may be an inner link of the drivechain. Each of the teeth in the second subset of teeth may be configuredto apply lateral pressure in a second direction to a respective link ofa bicycle drive chain; such a link may be an outer link of the drivechain. Each of the teeth in the first subset of teeth may have a topsurface that may be offset from a centerline of the drive chain when thechain ring and the drive chain are placed in operative position. Each ofthe teeth in the first subset of teeth and each of the teeth in thesecond subset of teeth may have top surfaces. The top surfaces may benot symmetrically arranged along a centerline of the drive chain whenthe ring and the drive chain are placed in operative position.

A drive system for a bicycle may include a drive chain and a chain ring.The drive chain may include a plurality of links. A first link may havea first inner surface at a first plane and an adjacent second link mayhave a second inner surface at a second plane facing the first innersurface of the first link. A link planar separation may be measured as ashortest distance between the first plane and the second plane. Thechain ring may be configured to removably interconnect with the drivechain. The chain ring may include a plurality of teeth joined to oneanother and serially arranged. The plurality of teeth may include afirst tooth and an adjacent second tooth. The first tooth may have afirst outer surface at a third plane capable of contacting the firstinner surface and the second tooth may have a second outer surface at afourth plane capable of contacting the second inner surface. A toothplanar separation may be measured as a shortest distance between thethird plane and the fourth plane. The tooth planar separation may be atleast as great as the link planar separation.

The first tooth may have a first cross sectional shape and the secondtooth may have a second cross sectional shape. The first link may be aninner link and the second link may be an outer link. The first tooth maybe configured to apply lateral pressure in a first direction to thefirst link. The second tooth may be configured to apply lateral pressurein a second direction to the second link. The first tooth may have a topsurface that may be offset from a centerline of the drive chain. Thefirst tooth and the second tooth may each have a top surface. The topsurfaces may be not symmetrically arranged along a centerline of thedrive chain. Each of the plurality of teeth may have a thickness and thethickness of each of the plurality of teeth at its respective thickestpoint may be substantially identical.

In another embodiment, a drive system for a bicycle may include a drivechain and a chain ring. The drive chain may have a plurality of links. Afirst link may have a first inner surface. The first inner surface mayhave a centerpoint. An adjacent second link may have a second innersurface facing the first inner surface of the first inner link. Thesecond inner surface may have a centerpoint. A link distance may bemeasured as a shortest distance between the centerpoint of the firstinner surface and the centerpoint of the second inner surface. The chainring may be configured to removably interconnect with the drive chain.The chain ring may include a plurality of teeth joined to one anotherand serially arranged. The chain ring may include a first tooth and anadjacent second tooth. The first tooth may have a first outer surfacehaving a centerpoint at its thickest part. The centerpoint of the firsttooth may be capable of contacting the first inner surface. The secondtooth may have a second outer surface having a centerpoint at itsthickest part. The centerpoint of the second tooth may be capable ofcontacting the second inner surface. A tooth distance may be measured asa shortest distance between the centerpoint of the first outer surfaceand the centerpoint of the second outer surface. The tooth distance maybe at least as great as the link distance.

The first tooth may have a first cross sectional shape and the secondtooth may have a second cross sectional shape. The first link may be aninner link and the second link may be an outer link. The first tooth maybe configured to apply lateral pressure in a first direction to thefirst link. The second tooth may be configured to apply lateral pressurein a second direction to the second link. The first tooth may have a topsurface that may be offset from a centerline of the drive chain. Thefirst tooth and the second tooth may each have a top surface. The topsurfaces may be not symmetrically arranged along a centerline of thedrive chain. Each of the plurality of teeth may have a thickness. Thethickness of each of the plurality of teeth at its respective thickestpoint may be substantially identical.

In another embodiment, a drive system for a vehicle may have a drivechain and a chain ring. The drive chain may have a plurality of linksand a centerline. The chain ring may have a plurality of teeth joined toone another and serially arranged. Each of the plurality of teeth may beconfigured to interfit with one of the plurality of links of the drivechain. The thickness of each of the plurality of teeth at its respectivethickest point may be substantially identical. Each of the plurality ofteeth may have a top surface having a centerline. Each centerline ofeach top surface of each tooth may be offset laterally in a firstdirection from the centerline of the drive chain in the same direction.Each of the plurality of teeth may have a base having a centerline. Eachcenterline of each base of at least a plurality of teeth may be offsetlaterally in the first direction from the centerline of the drive chain.

Each centerline of each top surface of each tooth may be offset from thecenterline of the drive chain in the outboard direction. Each centerlineof each top surface of each tooth may be offset from the centerline ofthe drive chain in the inboard direction.

Each tooth may be configured to place a lateral force on a respectivelink of the drive chain. A first tooth may be configured to place afirst lateral force on a first drive chain link in the first direction.A second tooth may be configured to place a second lateral force on asecond drive chain link in a second direction. The first tooth may beadjacent the second tooth. At least one tooth may be positionedcircumferentially between the first tooth and the second tooth.

In another embodiment, a drive system for a vehicle may include a drivechain and a chain ring. The drive chain may have a plurality of linksand a centerline. The chain ring may have a plurality of teeth joined toone another and serially arranged. Each of the plurality of teeth may beconfigured to interfit with one of the plurality of links of the drivechain. Each of the plurality of teeth may have a thickness and thethickness of each of the plurality of teeth at its respective thickestpoint may be substantially identical. Each of the plurality of teeth mayhave a top surface and a base. The top surfaces of the teeth may beasymmetrically arranged about the centerline of the drive chain. Thebases of the teeth may be asymmetrically arranged about the centerlineof the drive chain.

Each centerline of each top surface of each tooth may be offset from thecenterline of the drive chain in the same direction. Each centerline ofeach top surface of each tooth may be offset from the centerline of thedrive chain in an outboard direction. Each centerline of each topsurface of each tooth may be offset from the centerline of the drivechain in an inboard direction.

Each tooth may be configured to place a lateral force on a respectivelink of the drive chain. A first tooth may be configured to place afirst lateral force on a first drive chain link in a first direction anda second tooth may be configured to place a second lateral force on adrive chain link in a second direction. The first tooth may be adjacentthe second tooth. At least one tooth may be positioned circumferentiallybetween the first tooth and the second tooth.

In another embodiment, a drive system for a vehicle may include a drivechain and a chain ring. The drive chain may include a plurality of innerlinks and a plurality of outer links. Each link may comprise an innerplate and an opposite outer plate, each inner plate having a first innersurface facing the outer plate, and each outer plate having a secondinner surface facing the inner plate. The chain ring may have aplurality of teeth joined to one another and serially arranged. Each ofthe plurality of teeth may be configured to interfit with a respectiveone of the plurality of links of the drive chain. Each of the pluralityof teeth may have a thickness and the thickness of each of the pluralityof teeth at its respective thickest point may be substantiallyidentical. The plurality of teeth may comprise a first set of teeth anda second set of teeth. Each of the plurality of teeth may have a firstouter surface and a first inner surface. Each of the inner surface andthe outer surface of each of the first set of teeth may be permitted tocontact a corresponding inner surface of one of the inner or outer plateof a respective chain link with which it interfits. At least one portionof one of the first outer surface and the first inner surface of each ofthe second set of teeth may be configured to remain spaced from only oneof the first and second inner surfaces of the respective link with whichit interfits, in operative position.

The at least one portion of the second set of teeth may be spaced fromthe outer plate. The at least one portion of each of the second set ofteeth may be spaced from the inner plate.

Each of the second set of teeth may be configured to contact only one ofthe inner plate and the outer plate. Each of the second set of teeth maybe configured to contact the inner plate. Each of the second set ofteeth may be configured to contact the outer plate.

In another embodiment, a drive system for a bicycle may include a chainand a chain ring. The chain may have a centerline. The chain ring may beconfigured to removably interconnect with the drive chain. The chainring may include a plurality of teeth joined to one another and seriallyarranged. An average tooth position of the plurality of teeth may beoffset from the chain centerline when in operative position. Each of theplurality of teeth may have a thickness. The thickness of each of theplurality of teeth at its respective thickest point may be substantiallyidentical.

Each top surface of each of the plurality of teeth may be offset fromthe chain centerline when in operative position. The teeth may bearranged asymmetrically about the chain centerline when in operativeposition. At least a first tooth may be configured to apply a firstlateral force to the chain. At least a second tooth may be configured toapply a second lateral force to the chain. The first lateral force andthe second lateral force may be applied in substantially oppositedirections.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1A is a side view of a conventional chain;

FIG. 1B is a side view of a conventional chain;

FIG. 2 is a side view of a conventional chain ring;

FIG. 3 is a side view of one embodiment of a chain ring in accordancewith the disclosure;

FIG. 4 is a perspective view of the chain ring of FIG. 3 from the sideof one plurality of teeth;

FIG. 5 is a perspective view of the chain ring of FIG. 3 from the sideof another plurality of teeth;

FIG. 6 is a end view of the chain ring of FIG. 3;

FIG. 7 is a partial cross-sectional view of the chain ring of FIG. 3taken along line 7-7 of FIG. 4;

FIG. 8 is a side view of a plurality of teeth showing one embodiment ofa shape of the teeth;

FIG. 9 is a perspective view showing the interaction of the chain ringof FIG. 3 with a portion of a drive chain; and

FIG. 10 is a perspective view showing the interaction of anotherembodiment of a chain ring according to the disclosure with a portion ofa drive chain.

In describing the preferred embodiment of the invention which isillustrated in the drawings, specific terminology will be resorted tofor the sake of clarity. However, it is not intended that the inventionbe limited to the specific term so selected and it is to be understoodthat each specific term includes all technical equivalents which operatein a similar manner to accomplish a similar purpose. For example, theword connected or terms similar thereto are often used. They are notlimited to direct connection, but include connection through otherelements where such connection is recognized as being equivalent bythose skilled in the art.

DETAILED DESCRIPTION OF THE INVENTION

In this detailed description, various terms relating to direction may beused. The elements discussed herein relate to a bicycle. Because, in itsoperable position, a bicycle is oriented generally vertically, i.e.,perpendicular to the ground, the direction terms refer to the positionof an element relative to gravity when the bicycle is in its operableposition. Accordingly, for example, the term “downwardly” refers to thedirection towards the ground when the bicycle is in its operableposition, and the term “forwardly” relates to a direction towards afront wheel of the bicycle when it is in its operable position. Further,the terms “inboard” and “outboard” may be used. The term “inboard”describes a position between one item and a vertical plane substantiallybisecting the bicycle. The term “outboard” describes a position of anobject laterally farther from the vertical centerplane of the bicycle.In addition, the terms “bicycle” and “bike” are used hereininterchangeably. A person having ordinary skill in the art willunderstand that if something is referred to as one, it can refer to theother.

One embodiment of a chain ring 300 is shown in FIGS. 3-8. In somerespects, the chain ring 300 has a conventional design. For example, thechain ring 300 has a central bore 302 through which a bicycle crank (notshown) may pass. The bicycle crank and/or other hardware may be used tomount the chain ring 300 in operative position on a bicycle (not shown)in any conventional manner. A plurality of teeth 304 may be joined orconnected to one another and may be serially arranged and radiallyspaced around a circumference 306 of the chain ring 300.

As may be best seen from the views shown in FIGS. 4-7, the teeth 304 maybe separated into two subsets that have differing shapes. A first subsetof teeth may include first tooth 400, second tooth 402, and third tooth404. A second subset of teeth may include fourth tooth 406, fifth tooth408, and sixth tooth 410. As will be apparent to a person havingordinary skill in the art, each tooth in the first subset of teeth maybe substantially identical to one another. Similarly, each tooth in thesecond subset of teeth may be substantially identical to one another. Inthe illustrated embodiment, each tooth on the chain ring 300 is eitherone of the first subset of teeth or the second subset of teeth. However,in other embodiments, a chain ring may include one or more teeth thathave a shape and size that do not match the size and shape of one of thefirst and second subset of teeth as may be desired. In the illustratedembodiment, teeth from the first and second subsets may be interspersedor alternated with one another. That is, each tooth in the first subsetmay be adjacent two teeth from the second subset. For example, the firsttooth 400 of the first subset may be between the fourth tooth 406 andthe fifth tooth 408 of the second subset. Similarly, each tooth in thesecond subset may be adjacent two teeth from the first subset. Forexample, the fifth tooth 408 of the second subset may be between thefirst tooth 400 and the second tooth 402 of the first subset.

The determination of whether a tooth is in the first subset or thesecond subset may be made by considering the shape and size of therespective tooth at its thickest point. In the illustrated embodiments,the widest or thickest point of each of the plurality of teeth may be atits base. However, in another embodiment, the thickest point of arespective tooth may be elsewhere on the tooth. In the presentembodiment, where a particular configuration is described as being atthe “base” of the tooth, a person of ordinary skill in the art willunderstand that term to include a thickest point of a tooth, regardlessof where it appears along a height of the tooth. Similarly, the terms“thickness” and “width” and their related forms may be usedinterchangeably in the present disclosure. A person having ordinaryskill in the art will understand that the terms “width” and “thickness”refer to the dimension of a tooth or ring generally perpendicular to thedriving direction of the tooth and ring. In many embodiments, each ofthe plurality of teeth may have a thickness. The thickness of each ofthe plurality of teeth at its respective thickest point may besubstantially identical to the thickness of each of the remaining teethin the plurality of teeth at their respective thickest points.

The shape and size of each tooth at a top surface may be best seen inFIG. 6 and the shape and size of each tooth at a thickest point thereofmay be best seen in FIG. 7.

Because each tooth in the first subset of teeth is substantiallyidentical, each respective tooth in the first subset may be described inthe same manner and may have the same properties as the first tooth 400,which will be described herein. Because each tooth in the second subsetof teeth is substantially identical, each respective tooth in the secondsubset may be described in the same manner and may have the sameproperties as the fifth tooth 408, which will be described herein.

As shown in FIG. 6, the top surface of 604 of the first tooth 400 may besubstantially rectangular. The top surface 604 may have a length 600 anda width or thickness 602. The thickness of the first tooth 400 mayincrease from its top surface 604 to its base 608 (see FIG. 4) in afirst direction 680 outward on a first side 610 of the first tooth 400,and thus the first side 610 may be considered tapered. In the embodimentillustrated in FIG. 6, the first direction 680 may be an outboarddirection.

As shown in FIG. 7, at its base 608, the first tooth 400 may have afirst cross sectional shape. In some embodiments, the first crosssectional shape may be a rectangular cross sectional shape. At thethickest point 608, the first tooth 400 may have a length 700 and athickness 702. The thickness 702 may be greater than the thickness 602.

As shown in FIG. 6, the top surface 654 of the fifth tooth 408 may besubstantially hat-shaped. The top surface 654 may have a length 650, athickness 652 at its narrowest point (the “brim”), and a thickness 653at its widest point (the “crown”). The thickness of the widest part ofthe fifth tooth 408 may increase from its top surface 654 to its base658 (see FIG. 4) in a second direction 690 outward on a second side 660of the fifth tooth 408. In some embodiments, such as the one shown, thefifth tooth 408 may widen more greatly along a length 670 that is aboutone-half of the length 650 of the fifth tooth 408. In the embodimentshown in FIG. 6, the second direction is an inboard direction.

As shown in FIG. 7, at its base 658, the fifth tooth 408 may have asecond cross-sectional shape. In some embodiments, the second crosssectional shape may be a hat-shaped cross-sectional shape. At the base658, the fifth tooth 408 may have a length 750, a thickness 752 at itsnarrowest point, and a thickness 753 at its widest point. The thickness753 at the widest point may be greater than the thickness 653 at thewidest point at the top surface 654 of the fifth tooth 408.

As may be best seen in FIG. 6, a portion of each tooth may be alignedwith a portion of each other tooth. As may be seen, the first tooth 400has a rectangular top surface 604 having a length 600 and a width 602.The fifth tooth 408 in its narrow portion can also be considered to havea rectangular surface having a length 650 and a width 652. In someembodiments, the length 600 of the first tooth 400 may be substantiallyidentical to the length 650 of the fifth tooth 408. In some embodiments,the width 602 of the first tooth 400 may be substantially identical tothe width 652 of the fifth tooth 408. In many embodiments, the teeth400, 408 may be arranged such that these identical rectangular portionsare aligned with each other around the circumference 306 of the chainring 300.

In other embodiments, the size, shape, and placement of the top surfacesof the teeth may vary from the exemplary designs shown. While theillustrated embodiments show each tooth having a rectangular top surfaceportion, the top surfaces of the teeth may have non-rectangular shapesand may have shapes different from one another. In some embodiments, thetop surfaces may be offset from one another.

In the embodiment shown, the thickness 653 of the fifth tooth 408 may begreater at the widest point of its top surface 654 than the thickness602 of the first tooth 400 at the widest point of its top surface. Aswill be seen in FIG. 10 below, in some embodiments, the fifth tooth 408may be designed such that the fifth tooth 408 may have only arectangular portion at the top surface 654 having the thickness 652.Such a taper may be desirable in some embodiments, and accordingly, theincrease in thickness to a thickness 653 may be optional in someembodiments.

Further, each tooth 400, 408 may be configured to have one side that ismore highly tapered than the other, or one side may be tapered and theopposite side may not be tapered at all. In the embodiment illustratedin FIGS. 6 and 7, each tooth 400, 408 may have a respective taperedside. The first side 610 of the first tooth 400 may be the tapered ormore tapered side and the second side 660 of the second tooth 408 may bethe tapered or more tapered side. Each tooth 400, 408 may similarly havea less tapered or substantially planar side. The second side 612 of thefirst tooth 408 may be less tapered or the substantially planar side andthe first side 662 of the second tooth 408 may be less tapered or thesubstantially planar side. While this feature of tapering in oppositedirections may be seen in FIGS. 6 and 7, it may be more apparent in acomparison of the views of FIGS. 4 and 5, showing a perspective view ofthe chain ring from opposite directions. In some embodiments, theopposite directions and magnitudes of the taper may be designed tofacilitate a function of the teeth 400, 408, namely, to create opposinglateral forces on adjacent links of a drive chain. The teeth 400, 408may be configured such that the more tapered side 610, 660 of therespective tooth 400, 408 may be the side that is configured to apply alateral force to a drive chain link. The respective opposite, lesstapered side 612, 662 may be configured to be spaced from aninterfitting drive chain link or to merely be permitted to contact theinterfitting link slightly. These features of the drive train as a wholewill be disclosed in greater detail in connection with at least FIGS. 9and 10.

Looking now at FIG. 7, the thicknesses of the teeth may also beunderstood in relation to each other. In many embodiments, the thickness702 of the first tooth 400 may desirably be substantially identical tothe thickness 753 of the fifth tooth 408 at its widest point. In manyembodiments, the length 700 of the first tooth 400 may be substantiallyidentical to the length 754 of the fifth tooth 408. Thus, even thoughthe cross-sectional shapes of the teeth may differ, each of theplurality of teeth may have substantially the same width or thicknessand substantially the same length.

Turning now to FIG. 8, a closer side view of the first tooth 400 and thefifth tooth 408 from the inboard side may be seen. The first tooth 400may have a leading edge 800 and a trailing edge 802. The fifth tooth 408may have a leading edge 810 and a trailing edge 812. In the embodimentshown, the each edge 800, 802, 810, 812 of each tooth may angle in thedirection of rotation. The use of such an angle may provide a variety offunctions, such as, improving the mating of the teeth 304 with a drivechain (not shown). Such an angled portion is merely one example of anappropriate tooth shape. Within the present disclosure, each tooth maybe described as having a base, and various features of the teeth at thebase may be described. The base of a tooth may be considered to be thegeneral area on the tooth where it begins projecting from the centralportion of the chain ring. As an example only, the base of the firsttooth 400 may be in the area identified as 801 and the base of the fifthtooth 408 may be in the area identified as 803.

The illustrated embodiments disclose very few configurations of teeththat may be used. In many embodiments, it may be desirable for all theteeth to have similar shapes and sizes. In other embodiments, the teethmay vary in shape and size. In some embodiments, only teeth having ashape and size corresponding to one of the first subset and the secondsubset may be used. In other embodiments, teeth having a configurationdifferent from that disclosed as being desirable for the first andsecond subset may be used. In many embodiments, it may be desirable forthe chain ring to include substantially the same number of teeth in thefirst subset and the second subset. In many embodiments, it may bedesirable for the chain ring to have an alternating pattern of teeth inthe first subset and teeth in the second subset around the entirecircumference. In the disclosed embodiments, the crown portion of thehat-shaped cross section in the second subset of teeth is shown as beingone half the length of the remainder of the tooth. However, in otherembodiments, the crown portion may be longer or shorter, based on thecircumference of the ring or the number of teeth thereon, or for anyother reason deemed relevant by a designer. In other embodiments, ratherthan the leading and trailing edges both being angled in the directionof rotation, the leading edge may be angled away from the direction ofrotation to provide a reduced surface area for the tooth at the topsurface. In other embodiments, the leading and trailing edges may notinclude any substantial taper. Other modifications to the design arepossible and will be understood by a person having ordinary skill in theart to fall within the scope of the disclosure.

Turning now to FIG. 9, the interaction of the chain ring teeth and thedrive chain is shown. FIG. 9 shows the interaction and relative positionof one outer link of a drive chain with a tooth of the second subset andthe interaction and relative position of the two flanking inner links ofa drive chain with teeth of the first subset. As is conventional, thechain ring may be configured to removably interconnect with the drivechain in order to drive or propel the bicycle. A person having ordinaryskill in the art will recognize that in operative position, a pluralityof many more chain links, both inner and outer, will be present andengaged with the teeth and other parts to drive the bicycle. Only threelinks are shown in this FIG.

Looking first at the first tooth 400, the first tooth 400 may beconfigured to fit within or interfit with a respective first link 904 ofthe drive chain in operative position. In the illustrated embodiment,the first link 904 may be an inner link. A first face 900 of the firsttooth 400 may contact a first plate 902 of a first link 904 of the drivechain. The first face 900 of the first tooth 400 may correspond to themore tapered side 610 of the first tooth 400. This contact between theface 900 and the first link 904 may apply a lateral pressure or force onthe first link 904 in the first lateral direction 680. In thisembodiment, the first lateral direction may be outboard. The drive face930 of the first tooth 400 may contact a roller 932 of the drive chainto impart driving force to the drive chain and other drive trainelements. The first tooth 400 may also have a second face 990, which maycorrespond to the less tapered face 612 of the first tooth 400. Thesecond face 990 may be configured to be spaced from the second plate 994of the first link 904 of the drive chain. In other embodiments, thesecond face 990 may be permitted to contact the second plate 994 of thefirst link of the drive chain. In some embodiments, the configuration ofthe second face 990 as a substantially planar surface in conjunctionwith the remaining features of the configuration (which will bedescribed in greater detail below) may enable the second face 990 toremain spaced from the second plate 994 in use.

Looking next at the fifth tooth 408, the fifth tooth 408 may beconfigured to fit within or interfit with a respective second link 910of the drive chain. In the illustrated embodiment, the second link 910may be an outer link. The outer face 906 of the fifth tooth 408 maycontact a second plate 908 of the second link 910 of the drive chain.The outer face 906 of the fifth tooth 408 corresponds to the moretapered side 660 of the fifth tooth 408. This contact between the face906 and the second link 910 may apply a lateral pressure or force on thesecond link 910 in the second lateral direction 690. In this embodiment,the second lateral direction may be inboard. In some embodiments, thefifth tooth 408 may also engage an edge 912 of an adjacent first link904, but may not apply a substantial force thereto. The drive face 940of the fifth tooth 408 may contact a roller 942 of the drive chain toimpart driving force to the drive chain and other drive train elements.The fifth tooth 408 may also have a second face 992, which maycorrespond to the less tapered face 662 of the fifth tooth 408. Thesecond face 992 may be configured to be spaced from the second plate 996of the second link 910 of the drive chain. In other embodiments, thesecond face 992 may be permitted to contact the second plate 996 of thesecond link 910 of the drive chain. In some embodiments, theconfiguration of the second face 992 as a substantially planar surfacein conjunction with the remaining features of the configuration, such asa common thickness between all the teeth (which will be described ingreater detail below) may enable the second face 992 to remain spacedfrom the second plate 996 in use.

Looking at FIG. 1, any chain 150 may have a centerline 120. As may beseen in FIG. 9, the first tooth 400 and the fifth tooth 408 may bearranged such that their top surfaces are offset from the centerline 980of the chain. The first tooth 400 may taper to a first rectangular topface 920. The fifth tooth 408 may taper to include a second rectangularportion of the top face 922. The first rectangular top face 920 and thesecond rectangular top face 922 may be aligned with each other, as wasalso discussed in connection with FIG. 6. Comparing the positions of thefirst rectangular top face 920 and the second rectangular top face 922relative to the centerline 980 of the drive chain, it is apparent thatthe first rectangular top face 920 and the second rectangular top face922 may be offset laterally from the centerline 980. The particularlateral offset between the top faces 920 and 922 may vary depending onthe desires of a designer. However, in many embodiments, the top faces920 and 922 may be positioned such that they are not symmetrical aboutthe centerline 980 of the drive chain. As may be seen, the top surface920 may have a first top surface centerline 950, and top surface 922 mayhave a second top surface centerline 950. It will be understood by aperson having ordinary skill in the art that the respective centerline950, 952 of a respective top surface 920, 922 of a respective tooth 400,408 may be defined as the line defining the lateral middle of therespective top surface 920, 922 between a respective first top surfaceedge 954, 956 and a respective second top surface edge 958, 960. In theembodiment illustrated in FIG. 9, the first top surface edge 954, 956may be an outermost edge and the second top surface edge 958, 960 may bean innermost edge. In another embodiment, the first top surface edge954, 956 may be an innermost edge and the second top surface edge 958,960 may be an outermost edge.

As may be seen in FIG. 9, the respective centerlines 950 and 952 may beboth offset laterally from the centerline 980 of the drive chain inoperative position. In the illustrated embodiment, the respectivecenterlines 950, 952 may be offset laterally from the centerline 980 inthe same direction, namely, an inboard direction. In another embodiment,the centerlines may be offset laterally in an outboard direction or mayeach be offset laterally in a different direction.

In addition, the teeth 400 and 408 and the remainder of the plurality ofteeth may each be considered to have a position across a thickness ofthe chain ring. This relationship may be best seen in FIG. 6. Comparingthe view of FIG. 6 to the view of FIG. 9, and considering thedescription in the preceding paragraphs, each of the plurality of teethmay be considered to have a position relative to the centerline 980 ofthe chain. In some embodiments, the tooth position of a tooth may bedefined as the centerline of the respective tooth at a base of thattooth. As shown in FIG. 9, the centerline 950 of the tooth 400 and thecenterline 952 of the tooth 408 are both offset from the centerline 980of the chain. Accordingly, an evaluation of the centerlines at the basesmay reveal an average tooth position for the plurality of teeth as awhole. In many embodiments, such as the one shown in FIG. 9, the averagetooth position may be offset from the centerline 980 of the drive chainin operative position.

In addition, the top surfaces 920 and 922 may also be arranged laterallyasymmetrically about the centerline 980 of the drive chain in operativeposition. When viewing the top surfaces 920 and 922 relative to thecenterline 980, it is apparent that lateral symmetry is not present.Indeed, FIG. 9 shows both the top surface 920 and the top surface 922may be offset laterally from the chain centerline 980. Both top surfaces920, 922 may be offset laterally in the same direction from the chaincenterline 980. In the illustrated embodiment, the top surfaces 920, 922may be offset laterally on an inboard side of the chain centerline 980.In another embodiment, the top surfaces 920, 922 may both be offsetlaterally from the chain centerline 980 in an outboard direction. Inanother embodiment, the top surfaces 920, 922 may be offset laterally indifferent directions from the chain centerline 980 or otherwise offsetin another manner that is asymmetrical.

Further, the respective bases 608, 658 of the teeth 400, 408 may have asimilar relationship to the chain centerline 980 as their top surfaces920, 922. As may be seen, the first base 608 may have a first basecenterline 962, and the second base 658 may have a second basecenterline 964. It will be understood by a person having ordinary skillin the art that the respective centerline 962, 964 of a respective base608, 658 of a respective tooth 400, 408 may be defined as the linedefining the lateral middle of the respective base 608 between arespective first base side 966, 968 and a respective second base side970, 972. In the embodiment illustrated in FIG. 9, the first base side966, 968 may be an outermost side and the second base side 970, 972 maybe an innermost side. In another embodiment, the first base side 966,968 may be an innermost side and the second base side 970, 972 may be anoutermost side.

As may be seen in FIG. 9, the respective centerlines 962 and 964 may beboth offset laterally from the centerline 980 of the drive chain inoperative position. However, in many embodiments, the first basecenterline 962 may be aligned, such as coincident, with the chaincenterline 980. In the illustrated embodiment, the respectivecenterlines 962, 964 may be offset laterally from the centerline 980 inthe same direction, namely, an inboard direction. In another embodiment,the centerlines may be offset laterally in an outboard direction or mayeach be offset laterally in a different direction.

In addition, the bases 608, 658 may also be arranged laterallyasymmetrically about the centerline 980 of the drive chain in operativeposition. When viewing the bases 608, 658 relative to the centerline980, it is apparent that lateral symmetry is not present. In theillustrated embodiment, the first base 608 may be arranged substantiallyon or symmetrically about the chain centerline 980, while the secondbase 658 may be offset laterally from the centerline 980, in thisembodiment in an inboard direction. This difference in offset may createasymmetry in positioning.

In some embodiments, only one of the top surfaces may be offsetlaterally from a centerline of the drive chain in operative position. Insome embodiments, only the top surface of the first tooth may be offsetlaterally from a centerline of the drive chain when the chain ring andthe drive chain are placed in operative position. The top surface of thesecond tooth may be positioned laterally symmetrically around the drivechain centerline. In other embodiments, the top surfaces of the firsttooth and the second tooth may be offset laterally from the drive chaincenterline in opposite directions. In those embodiments, the topsurfaces may be arranged such that they are not laterally symmetricallyarranged with respect to one another along a centerline of the drivechain when the chain ring and the drive chain are placed in operativeposition.

It will be apparent to one of ordinary skill in the art that, among thereasons that each respective tooth in the first subset of teeth may bepositioned between two teeth in the second subset of teeth (and viceversa) in an alternating pattern around the chain ring, is that a drivechain typically has alternating inner links and outer links along itslength. The chain ring may be configured to have alternating teethconfigured to fit into the appropriate width and shape of alternatinglink. It will be apparent to a person having ordinary skill in the artthat while the illustrated embodiment envisions the first subset ofteeth applying a lateral force to the chain in an outboard direction andthe second subset of teeth applying a lateral force to the chain in aninboard direction, the teeth could be oppositely oriented and positionedon the chain ring to apply force in the opposite directions. A personhaving ordinary skill in the art is able to make such a modificationwithout undue experimentation.

FIG. 10 illustrates a few modifications that may be made to theconfiguration. In brief, the degree of taper of the second tooth ischanged and the directions of taper of the first and second teeth arereversed. However, the comparative features of the teeth remain, such asthe inclusion of tapers in opposite directions, the spacing of the facesof the teeth relative to the links of the chain, the differing crosssectional shapes of the teeth, and any other features not specificallymentioned.

In the embodiment of FIG. 10, the top surface 1654 of the fifth tooth1408 may be rectangular instead of hat-shaped. In this embodiment, thefifth tooth 1408 tapers more greatly toward the top surface than thefifth tooth that is shown and described in the embodiment above.Accordingly, the top surface 1654 may be rectangular or substantiallyrectangular. A person having ordinary skill in the art will be able toeasily select an appropriate taper as the designer deems appropriate.

In addition, the directions of taper are reversed from those of FIG. 9.Looking first at the first tooth 1400, the first tooth 1400 may beconfigured to fit within an inner link 1904 of the drive chain. Thefirst tooth 1400 may project outwardly in a first direction 1680. Theouter face 1900 of the first tooth 1400 may contact a first plate 1902of an inner link 1904 of the drive chain. This contact between the face1900 and the inner link 1904 may apply a lateral pressure on the innerlink 1904 in the first lateral direction 1680. In this embodiment, thefirst direction 1680 may be inboard.

Looking next at the fifth tooth 1408, the fifth tooth 1408 may beconfigured to fit within an outer link 1910 of the drive chain. Thefirst tooth 1408 may project outwardly in a second direction 1690. Theouter face 1906 of the fifth tooth 1408 may contact a second plate 1908of an outer link 1910 of the drive chain. This contact between the face1906 and the outer link 1910 may apply a lateral pressure on the outerlink 1910 in the second lateral direction 1690. In some embodiments, thefifth tooth 1408 may also engage an edge 1912 of an adjacent inner link1904, but may not apply a substantial force thereto. In this embodiment,the second lateral direction 1690 may be outboard.

The inclusion of FIG. 10 illustrates merely a few changes that caneasily be made by a person having ordinary skill in the art to thedesign while still within the scope of the disclosure. Each of thesemodifications will be understood to form a part of the disclosure andclaims herein.

As may be seen, the top surface 1920 of the first tooth 1400 may have afirst top surface centerline 1962, and the top surface 1922 of thesecond tooth 1408 may have a second top surface centerline 1952. It willbe understood by a person having ordinary skill in the art that therespective centerline 1962, 1952 of a respective top surface 1920, 1922of a respective tooth 1400, 1408 may be defined as the line defining thelateral middle of the respective top surface 1920, 1922 between arespective first top surface edge 1954, 1956 and a respective second topsurface edge 1958, 1960. In the embodiment illustrated in FIG. 10, thefirst top surface edge 1954, 1956 may be an innermost edge and thesecond top surface edge 1958, 1960 may be an outermost edge. In anotherembodiment, the first top surface edge 1954, 1956 may be an outermostedge and the second top surface edge 1958, 1960 may be an innermostedge.

As may be seen in FIG. 10, the respective centerlines 1962 and 1952 maybe both offset laterally from the centerline 1980 of the drive chain inoperative position. In the illustrated embodiment, the respectivecenterlines 1962, 1952 may be offset laterally from the centerline 1980in the same direction, namely, an outboard direction. In anotherembodiment, the centerlines may be offset laterally in an inboarddirection or may each be offset in a different direction.

In addition, the top surfaces 1920 and 1922 may also be arrangedlaterally asymmetrically about the centerline 1980 of the drive chain inoperative position. When viewing the top surfaces 1920 and 1922 relativeto the centerline 1980, it is apparent that lateral symmetry is notpresent. Indeed, FIG. 10 shows both the top surface 1920 and the topsurface 1922 may be offset laterally from the chain centerline 1980.Both top surfaces 1920, 1922 may be offset laterally in the samedirection from the chain centerline 1980. In the illustrated embodiment,the top surfaces 1920, 1922 may be offset laterally on an outboard sideof the chain centerline 1980. In another embodiment, the top surfaces1920, 1922 may both be offset laterally from the chain centerline 1980in an inboard direction. In another embodiment, the top surfaces 1920,1922 may be offset laterally in different directions from the chaincenterline 1980 or otherwise offset in another manner that isasymmetrical.

Further, the respective bases 1608, 1658 of the teeth 1400, 1408 mayhave a similar relationship to the chain centerline 1980 as their topsurfaces 1920, 1922. As may be seen, the first base 1608 may have afirst base centerline 1950, and the second base 1658 may have a secondbase centerline 1964. It will be understood by a person having ordinaryskill in the art that the respective centerline 1950, 1964 of arespective base 1608, 1658 of a respective tooth 1400, 1408 may bedefined as the line defining the lateral middle of the respective base1608 between a respective first base side 1966, 1968 and a respectivesecond base side 1970, 1972. In the embodiment illustrated in FIG. 10,the first base side 1966, 1968 may be an innermost side and the secondbase side 1970, 1972 may be an outermost side. In another embodiment,the first base side 1966, 1968 may be an outermost side and the secondbase side 1970, 1972 may be an innermost side.

As may be seen in FIG. 10, the respective centerlines 1950 and 1964 maybe both offset laterally from the centerline 1980 of the drive chain inoperative position. However, in many embodiments, the first basecenterline 1962 may be aligned with the chain centerline 1980. In theillustrated embodiment, the respective centerlines 1962, 1964 may beoffset laterally from the centerline 1980 in the same direction, namely,an outboard direction. In another embodiment, the centerlines may beoffset laterally in an inboard direction or may each be offset laterallyin a different direction.

In addition, the bases 1608, 1658 may also be arranged laterallyasymmetrically about the centerline 1980 of the drive chain in operativeposition. When viewing the bases 1608, 1658 relative to the centerline1980, it is apparent that lateral symmetry is not present. In theillustrated embodiment, the first base 1608 may be arrangedsubstantially on or symmetrically about the chain centerline 1980, whilethe second base 1658 may be offset laterally from the centerline 1980,in this embodiment in an outboard direction. This difference in offsetmay create asymmetry in positioning.

The size, shape, and position of the teeth of the chain ring may beselected such that the nominal width of the teeth is greater than thenominal width of adjacent links. Returning to FIG. 1, the first innerlateral surface 110 of the outer link 100 may be considered to lie in,at, outside of, or along a first plane 130. A third inner lateralsurface 114 of the inner link 102 may be considered to lie in, at,outside of or along a second plane 140. The first inner lateral surface110 and the third inner lateral surface 114 of the respective links mayface one another. The link nominal width or link planar separation maybe measured as the shortest distance between the first plane 130 and thesecond plane 140 measured substantially perpendicular to the first plane130 and the second plane 140. One exemplary location of measurement isshown at 135.

Similarly, the first inner lateral surface 110 may have a firstcenterpoint 116. Because chain link plates are generally bothhorizontally and vertically symmetrical, the first centerpoint 116 maybe positioned at a point where the horizontal and vertical axes ofsymmetry intersect. The third inner lateral surface 114 may have asimilarly defined second centerpoint 118. A link distance may bemeasured as the shortest distance between the first centerpoint 116 andthe second centerpoint 118 of two adjacent links. One exemplary locationof measurement is shown at 137.

Turning now to FIG. 7, the outer face 780 of the first tooth 400 may besaid to lie in a third plane 785. The outer face 770 of the fifth tooth408 may be said to lie in a fourth plane 775. The tooth nominal width ortooth planar separation may be measured as the shortest distance betweenthe third plane 785 and the fourth plane 775 measured substantiallyperpendicular to the third plane 785 and the fourth plane 775. Oneexemplary location of measurement is shown at 787.

Similarly, outer face 780 of the first tooth 400 may have a firstcenterpoint 782. The first centerpoint 782 may be defined as thelongitudinal middle point of the widest section of the first tooth 400measured at the base. The outer face 770 of the fifth tooth 408 may havea similarly defined second centerpoint 772. A tooth distance may bemeasured as the shortest distance between the first centerpoint 782 andthe second centerpoint 772. One exemplary location of measurement isshown at 789.

In many embodiments, the amount of lateral pressure on the drive chainfrom the chain ring teeth may be determined by the relative positioningof these parts. In many embodiments, the tooth planar separation may begreater than the link planar separation. In many embodiments, the toothdistance may be greater than the link distance. In many embodiments,both will be true. Because the tooth shape may vary, it may be moremeaningful in some embodiments to measure a tooth planar separation, andin other embodiments, it may be more meaningful to measure a toothdistance. For example, if the outer face 770 of one tooth is notparallel to the outer face 780 of another tooth, it may be difficult orimpossible to judge a planar separation. In other embodiments, wherethere may be multiple discrete points that form an outer face of atooth, rather than a planar surface, selecting a centerpoint may becomplicated or impossible. In some embodiments with a single contactpoint between an outer tooth face and an inner surface of a chain link,that point may be considered the centerpoint. In some embodiments withmultiple discrete points of contact between an outer tooth face and aninner surface of a chain link, the most central point may be consideredto be the centerpoint. In many embodiments, however, the teeth and linksmay have a regular, symmetrical shape where either measurement can bemade and evaluated to determine the amount of lateral pressure that willbe created between the chain ring and the drive chain.

It will be apparent to a person having ordinary skill in the art thatthe measurements noted in the specification and claims may becomplicated to accurately measure. Manufacturing tolerances, wear, andthe like may cause variation in the size, shape, thickness, and positionof the chain ring teeth and various parts of any given drive chain.Accordingly, measurements may be taken at varying points along a chainring and/or drive chain. In some embodiments, an average actual relativemeasurement may be used. In other embodiments, a dimension as designedmay be considered. In addition, a variety of drive chains could be usedwith the chain ring disclosed in the present disclosure. In manyembodiments, the drive chain may be selected to have the size andspacing characteristics relative to the chain ring dimensions. In manyembodiments, drive chains that are commonly used with 9, 10, and 11speed bicycles are appropriate for use in the disclosed design.

While certain preferred embodiments of the present invention have beendisclosed in detail, it is to be understood that various modificationsmay be adopted without departing from the spirit of the invention orscope of the following claims.

The invention claimed is:
 1. A drive system for a bicycle, comprising: adrive chain having a plurality of links; wherein a first link has afirst inner surface and the first inner surface has a centerpoint and anadjacent second link has a second inner surface facing the first innersurface and the second inner surface has a centerpoint; and wherein alink distance may be measured as a shortest distance between thecenterpoint of the first inner surface and the centerpoint of the secondinner surface; and a chain ring configured to removably interconnectwith the drive chain, the chain ring comprising a plurality of teethjoined to one another and serially arranged; wherein the plurality ofteeth includes a first tooth and an adjacent second tooth; wherein thefirst tooth has a first outer surface having a centerpoint at itsthickest part that is capable of contacting the first inner surface, andthe second tooth has a second outer surface having a centerpoint at itsthickest part that is capable of contacting the second inner surface;wherein a tooth distance may be measured as a shortest distance betweenthe centerpoint of the first outer surface and the centerpoint of thesecond outer surface; wherein the tooth distance is at least as great asthe link distance; and wherein each of the plurality of teeth has athickness and the thickness of each of the plurality of teeth at itsrespective thickest point is substantially identical.
 2. The drivesystem for a bicycle according to claim 1, wherein the first tooth has afirst cross sectional shape and the second tooth has a second crosssectional shape.
 3. The drive system for a bicycle according to claim 1,wherein the first link is an inner link and the second link is an outerlink.
 4. The drive system for a bicycle according to claim 1, whereinthe first tooth is configured to apply lateral pressure in a firstdirection to the first link.
 5. The drive system for a bicycle accordingto claim 1, wherein the second tooth is configured to apply lateralpressure in a second direction to the second link.
 6. The drive systemfor a bicycle according to claim 1, wherein the first tooth has a topsurface that is offset from a centerline of the drive chain.
 7. Thedrive system for a bicycle according to claim 1, wherein the first toothand the second tooth each have a top surface and the top surfaces arenot symmetrically arranged along a centerline of the drive chain.
 8. Adrive system for a vehicle, comprising: a drive chain having a pluralityof links and a centerline; and a chain ring having a plurality of teethjoined to one another and serially arranged; wherein each of theplurality of teeth is configured to interfit with a respective one ofthe plurality of links of the drive chain; wherein each of the pluralityof teeth has a top surface having a centerline; wherein each of theplurality of teeth has a base having a centerline; wherein each of theplurality of teeth has a thickness, the thickness of each of theplurality of teeth at its respective widest point being substantiallyidentical; wherein each centerline of each base of at least first groupof the plurality of teeth is offset laterally in a first direction fromthe centerline of the drive chain; and wherein each centerline of eachtop surface of each tooth is offset laterally from the centerline of thedrive chain in the first direction and the centerlines of the topsurfaces of any two adjacent teeth are offset from one another.
 9. Thedrive system for a vehicle according to claim 8, wherein each centerlineof each top surface of each tooth is offset from the centerline of thedrive chain in an outboard direction.
 10. The drive system according toclaim 8, wherein each centerline of each top surface of each tooth isoffset from the centerline of the drive chain in an inboard direction.11. The drive system for a vehicle according to claim 8, wherein eachtooth is configured to place a lateral force on a respective link of thedrive chain.
 12. The drive system for a vehicle according to claim 11,wherein a first tooth of the plurality of teeth is configured to place afirst lateral force on a first drive chain link in the first directionand a second tooth of the plurality of teeth is configured to place asecond lateral force on a second drive chain link in a second direction.13. The drive system according to claim 12, wherein the first tooth isadjacent the second tooth.
 14. A drive system for a vehicle, comprising:a drive chain having a plurality of links and a centerline; and a chainring having a plurality of teeth joined to one another and seriallyarranged; wherein each of the plurality of teeth is configured tointerfit with a respective one of the plurality of links of the drivechain; wherein each of the plurality of teeth has a top surface and abase; wherein each of the plurality of teeth has a thickness, thethickness of each of the plurality of teeth at its respective thickestpoint being substantially identical; wherein the bases of the teeth arelaterally asymmetrically arranged about the centerline of the drivechain; wherein the top surfaces of the teeth are laterallyasymmetrically arranged about the centerline of the drive chain; whereinthe top surfaces of any two adjacent teeth are offset from one another;and wherein each centerline of each top surface of each tooth is offsetfrom the centerline of the drive chain in the same direction.
 15. Thedrive system for a vehicle according to claim 14, wherein eachcenterline of each top surface of each tooth is offset from thecenterline of the drive chain in an outboard direction.
 16. The drivesystem according to claim 14, wherein each centerline of each topsurface of each tooth is offset from the centerline of the drive chainin an inboard direction.
 17. The drive system for a vehicle according toclaim 14, wherein each tooth is configured to place a lateral force on arespective link of the drive chain.
 18. The drive system for a vehicleaccording to claim 17, wherein a first tooth of the plurality of teethis configured to place a first lateral force on a first drive chain linkin a first direction and a second tooth of the plurality of teeth isconfigured to place a second lateral force on a second drive chain linkin a second direction.
 19. The drive system according to claim 18,wherein the first tooth is adjacent the second tooth.
 20. A drive systemfor a vehicle, comprising: a drive chain having a plurality of innerlinks and a plurality of outer links, each link comprising an inboardplate and an opposite outboard plate, each inboard plate having a firstinner surface facing the outboard plate and each outboard plate having asecond inner surface facing the inboard plate; and a chain ring having aplurality of teeth joined to one another and serially arranged; whereineach of the plurality of teeth is configured to interfit with arespective one of the plurality of links of the drive chain; whereineach of the plurality of teeth has a thickness, the thickness of each ofthe plurality of teeth at its respective thickest point beingsubstantially identical; wherein the plurality of teeth comprises afirst set of teeth and a second set of teeth; wherein each of the firstset of teeth is configured to have a first cross-sectional shape at arespective base; wherein a second set of teeth is configured to have asecond cross-sectional shape at a respective base that is different fromthe first cross-sectional shape; wherein each of the plurality of teethhas a first outer surface and a first inner surface; wherein each of theinner surface and the outer surface of each of the first set of teeth ispermitted to contact a corresponding inner surface of one of the inboardor outboard plate of a respective chain link with which it interfits;wherein at least one portion of one of the first outer surface and thefirst inner surface of each of the second set of teeth is configured toremain spaced from only one of the first and second inner surfaces ofthe respective link with which each of the second set of teeth interfitsin operative position; and wherein each of the second set of teeth isconfigured to contact only one of the inboard plate and the outboardplate.
 21. The drive system for a vehicle according to claim 20, whereinthe at least one portion of the second set of teeth is spaced from theoutboard plate.
 22. The drive system for a vehicle according to claim20, wherein the at least one portion of each of the second set of teethis spaced from the inboard plate.
 23. The drive system for a vehicleaccording to claim 20, wherein each of the second set of teeth isconfigured to contact the inboard plate.
 24. The drive system for avehicle according to claim 20, wherein each of the second set of teethis configured to contact the outboard plate.